Muffler



C. DEMUTH April' 10, 1945.;

MUFFLER Filed Feb. 15 1944 2 Sheets-Sheet l.

L LI \\w INVENTOR O/A/PL 58 0011/ TH BY M 23 ML ATTORN EYS C. DEMUTH April 10, 1945.

MUFFLER Filed Feb. 15, 1944 2 Sheets-Sheet 2 INVENTORv CHAR; 3 06/7077? BY 7,4,4 cw qm A. ATTORNEYS Patented Apr. 10, 1945 UNITED STATES PATENT OFFICE MUFFLER Charles Demuth, Mineola, N. Y.

Application February 15, 1944,..SerialNo. 522,457

12 Claims.

This invention relates to muiiiers for silencing or reducing noises caused by or carried by a gas (such as exhaust gas from an internal combustion engine, air, vapor, steam or the like comp-ressible fluid) in its movement through or from a conduit.

A familiar application of this class of device is typified by the muliler employed in connection with the exhaust of an internal combustion engine. As illustrative of other applications, Ihave.

at the same time preventing or greatly retarding:

a reversal of the how of gas (suchas a backfire).

The invention consists of the novel feature, arrangement and combination of parts embodied by way of example in the structure hereinafter described' as illustrating the present preferred form of the invention, and the invention will be more particularly pointed out in the appended claims.

Further objects and advantages of the invention will more fully appear' from the following description taken in connection with the accompanying drawings which show, by way of example, present preferred embodiments of the invention.

Referring to the drawings Fig. 1 is a longitudinal sectional view, taken in a plane passing substantially through the aXis of a preferred embodiment of the invention, and showing the interior construction thereof;

Fig. 2 is'a transverse sectional view taken along the line 2-2 of Fig. 1 and showing certain details at the inlet end;

Fig. 3 is a transversesectional View taken along the line 3-3 of Fig. 1 and showing certain details at a zone intermediate the inlet and. outlet ends;

Fig. 4 is a view similar to Fig. 1 but showing a modified embodiment of the invention;

-Fig. 5 is a cross-sectional View taken at line 5-5 of Fig. 4 and Fig. 6 is a cross-sectional viewshowingsomewhat more clearly certain details common to the embodiments "of Figs. 1 and 4.

Referring more. particularly to Fig. l, l designates'ingeneral-the casingor main body structure of the mufiier which comprises two sections 2 and 3- of generally frusto-conical shape secured together at their bases such as by flange rings 4 and 5 integrally secured thereto as by welding, and bolted together around their peripheries by bolts such as 6. The outer small ends of the sections 2-.3 are provided with cylindrical sleeve portions l and 8, serving respectively as the inlet and outlet ends of the mufiler and providing means for attachment to suitable conduits. The casing lis substantially circular in cross-section and is provided on its inner face with a plurality of substantially trusto-conical annular rings such as 9-24 inclusive, which are suitably secured at their respective outer edges to the interior of the casing l, as by welding. It will be noted that the annular rings 9--24- are spaced axially in generally nested arrangement so that the small end of one ring extends into the large end of the succeeding ring or is directed into the large end of the succeeding ring. The inner edges of the rings 9-24 are spaced inwardly from the side wall of casing l and define the same general configuration as the casing i. It will also be noted that the bafile rings 9-.-24 inclusive taper inwardly in a direction from the inlet throat 1 toward the outlet throat 8, i. e., in the direction of flow through the muffler.

A centrally disposed series of substantially frusto-conical baffle members 25-31 inclusive is supported substantially along the axis of the casing l, i. e., the axis of the sleeves 'l8; in the presentembodiment such support being had from the central bafile member 30 which is provided with a plurality of spider arms 38, 39 (Fig. 3), 48 and 4| which carry integrally supported at their outer ends an annular flange 42 which is secured between the flanges 4 and 5 so as to rigidly support the baffle member 30 in substantially the axial position indicated in Fig. 1. An axially extending'bo'lt or threaded rod 43 (Fig. 1) extends through a hole provided in the baffle cone 30 and through corresponding holes in the remaining baflles 25-29 and 35-31 inclusive of the central series; these baffles being spaced one from the other by means of spacing sleeve such as 44, and the entire assembly being secured to the cone 30, such as by a nut 45. .In the present embodiment I have found it convenient to support the bafiles 31-34 inclusive directly from the baflie 30, as by welding the small ends of these frusto-conical membersto the insideof the member 39, as clear- 13; shown in Fig. 1.

The bafile members 25-31 inclusive extend outwardly from the axis of the mufiler and incline outwardly toward their large diameters in a direction from the inlet opening towards the outlet opening; with the outer circumferential edges of said central bafiles spaced inwardly from the inner edges of the outer series of baffles and defining the same general shape as that followed by the inner edges of the outer baflles. The assembly of central baiiles is disposed within the path of the flow of gas entering the inlet opening, and serves to deflect the gases outwardly and through the annular space defined between the respective inner edges of the outer series of baffies and the outer edges of the inner series of inner baflies 25-31 provides in eifect a plurality of annular nozzles providing annular orificesthrough which gases successively pass from the inlet to the outlet openings of the muffler; this arrangement being somewhat more clearly shown in Fig. 6. It is not essential, however, that every bafiie of one series have a corresponding baflie of the other series. It is noted that the annular area of the orifices of these successive nozzles is greater than the intake orifice, and this is controlled by the internal diameter of the outer series and. outer diameter of the inner series of said baflles.

In the present embodiment, the annular outer bafiies 9, l and 24 do not have any corresponding inner central bafiies but cooperate with the remaining baflies of the outer series to create a so-called vacuum or reduced pressure within the successive spaces defined between the outer baffles and the adjacent interior of the casing l. Similarly the spaces between the inner series of bafiles 25-31 inclusive and their supporting axle provide the so-called vacuum or reduced pressure due to the movement of gases in the manner above described. Additionally, the arrangement of bafiies, while permitting free passage of gas from the inlet to the outlet ends of the mufiier, substantially prevents a flow in the reverse direction; and in view of the relatively large annular vacuum spaces provided between the bafiies, any backfire will be practically prevented from causing any appreciable flow in a reverse direction out through the inlet of the muffler.

I have found that the preferable proportions for the mufiier are as follows: The outlet is generally the same size as the inlet and should not be appreciably smaller, but may be larger. The

maximum internal diameter (say, at the intermediate zone designated by the ring flange 42-) should be twice as great as the diameter "of the inlet opening, i. e., at least twice the area; and the axial length of the muiiler from the inner end of the inlet sleeve 1 to the inner end of the outlet sleeve 8 should be at least twice as great as the maximum diameter above referred to. I have obtained satisfactory results in an embodiment of a the invention where the inlet and. outlet openings were each three inches in diameter; the axial character of use, as will be understood by those skilled in the art. l.

Modification (Fig. 4)

In Fig. 4 I have shown a modification which in major particulars as to baffle arrangement and shape is similar to the embodiment previously described with reference to Fig. 1; and therefore the description of features common to both embodiments will not be repeated, and similar parts of Fig. 4 will be designated by corresponding reference numerals with an added prime suffix.

The mufiier casing I is shown in this embodiment as comprising the sections 2'3' joined to gether at the intermediate maximum diameter by a seam 46 which may be formed in any suitable manner such as by welding together flanged peripheral edges of the abutting sections. Instead of supporting the central bafile set from a single spider disposed at the median zone of the mufiier (as in the previously described embodiment), the central bafile set is supported from suitable spider rings, such as Q! and 48, rigidly secured within the respective inlet and outlet throats 1'-8', as by spot-welding. A tie-rod or bolt 43' passes through the hubs of the spider rings 41-48 and is rigidly supported thereby substantially along the axis of the mufiier. The baflle members 25-31' are threaded on to the rod 43' and are rigidly held in spaced relation by suitable spacing sleeves such as '34; and oppositely disposed spacing sleeves 49 and 50 serve to axially space the respectively opposite ends of the series of central baflies from the respectively adjacent spider rings 41 and 48. It will thus be seen that the core unit assembly of bafiles of the central series are rigidly supported axially of the muffler in the position corresponding to that previously described; but in this instance the support is had from the opposite ends of the mufiier instead of from a central zone as described in the previous embodiment.

It is noted that the embodiment of Fig. 1 permits ready disassembly and reassembly; and this is especially useful when the mufiier is used under such circumstances as require cleaning.

Operation I The gas flowing in through the inlet, such as l or I, passes through the annular rings, such as 9-I 0 or 9'l 0', and is gradually and progressively deflected or expanded outwardly by the inner baiiies 25-30 or 25'-30 toward and against the outer baflles Il-ll or l|-ll' to adjacent the median zone, and then is gradually and progressively deflected inwardly by the outer series ll-ZZ or l'i-22' toward or against the inner series of baflies 32-31 or 32-31'. The gas is thus caused to flow in the annular passage defined between the outer -edges of the inner bafiies and the inner edges of the outer baffles, such as 9-24 or 9'44, and thence outwardly through the annular baflle ring, such as 24 or 24', and outwardly through the outlet opening, such as 8 or 8'. During the flow of the gas through the muffler, the baffle arrangement produces a reduced pressure in the spaces betweenthe bafiles, as previously described; thus providing adjacent the interior surface of the muffler shell I or I a layer of reduced pressure or partial vacuum serving as sound absorber or dissipator. correspondingly, a central core of reduced pressure or partial vacuum is created'by the baffles of the central series of baiiles. Accordingly, the noises caused or carried by the moving flow of gas are insulated and absorbed or dissipated during the passage through the mufiler. In

I practical operation the invention has been found to be most eflicient in elimination of noises, preventing a reversal of now oi-gasesg-and eliminating -'the--creatiori of back pressurefwhich is-"e'speciallydesiraole ininternal combustion engines. "*I-Iaving thus described my'invention"with'par- *ticularity with-"reference to "presently preferred forms of the same, it will be obvious tot-hose skilled in the art afterunderstanding the inven- 1 tion-, tha-t various other changes and rnodifications may be mettle-therein Without departingirointhe scope" of the invention; and it is-my intention to cover intheappended claims such changes as come within'the scope of the invention.

' Wh'at-I'claim is:

l. A muiiier comprising a casing provided-with termediate said twoseries of bafiles a'free' "annular passage flaring outwardly from" the ."respective inlet and outlet endstowardsaid intermediate zone in general'iunnel shape.

" 2. A murdercomprisingasubstantially circular casing provided with"substantially axiallydisposed inlet and 'outlet'openings at respectively opposite ends, a firstseries of axially spaced baffles surrounding the. axis. of' atndextending inwardly of said casing inclined in' the general direction of said outletopeningand having their outer peripheriesrigidly secured to the interior of'said casing,.a second series of axially spaced baiiles extending outwardly from the axis of said casing inclined toward said outletopening and supported on an axially extending rodsupported from said casing, the baffles of said second series progressively increasing in outward extent'from adjacent .the respective inlet. and outlet ends to a zone intermediate said ends and the inwardly extending edges of. the baffles ofsaid first series being spaced. outwardly therefrom to provide intermediate .said two. seriesoflbafiies a free annular passage between said inlet and outlet openings.

3. A mufflerv comprising .a substantially .circular casing provided..with .fsubstantially axially disposed inlet and outletopenings at respectively .oppositeends, afirsts'eries' of axially spaced .l'rusto-conical ringbafiles whose large diameters are secured to the inner wall of said casing. and .whose small diameters are directed towardsaid outlet opening, whereby the bafiies provide suc-' cessive throats decreasing in area toward said outlet, a second series of axially spaced substantially circular bafiies extending outwardly from the axis Of said casing and inclined toward said outlet opening, the baffles of said second series progressively increasing in outward extent from adjacent the respective inlet and outlet ends to a zone intermediate said ends and the inwardly extending edges of the baffles of said first series being spaced outwardly therefrom to provide intermediate said two series of baffles a free annular passage between said inlet and outlet openings.

4. A muiiler comprising a substantially circular elongated casing provided at respectively opposite ends with inlet and outlet openings and progressively increasing in 'diameter'from adjacent said-respective openings to a maximum diameter at a'zone intermediatesaid ends, an outer series of axially spaced annular baiiles integrally-secu'red' within said casing and directed inwardly thereof and toward said outlet opening with their "-"innerperipheral edges spaced inwardly from and conforming to the general contour of said casing,

'- and an inner series of axially spaced baffles 're- *spectively extending in a direction outwardly from said axis and =1nclined-toward said outlet opening, the outer peripheral edges of said inner baffles being spaced inwardly from the inner-edges of's'aid 'outerbaiiles to define afree annular passage conforming to the general contour of said casing and interconnecting said inlet and outlet passages. 5. A' muffler comprising a substantially circular elongated'casing provided at'respectively opposite ends with inlet and outlet openings and progres- -sive'ly"increasing in diameter from adjacent-said --respective openings to a maximum diameter at azone'intermediate said ends, said maximum diameterbeing at least twice the diameter of said "inlet opening and said outlet opening being of a -diameter atleast substantially as large as the diameter of said inlet opening, an outer series of axially spaced annular bafiies integrally secured wlthin'said casing and directed inwardly thereof and toward'saidcutlet opening with their inner peripheral edgesspaced inwardly from and coniorming to the'generalcontour of said casing, and an inner series of axially spaced baflles re- 'spectively" extending in a direction outwardly "'fronisaid' axis and'inclined toward said outlet opening; the outer peripheral edges of said inner be-flies being spaced inwardly from the inner edges '1' of said outer baiiles to define a free annular passage conforming to the'general contour of said casing and interconnecting said inlet and outlet "passages.

6. A rhuiiler comprising a substantially circular "elongated casin'g'provided' at respectively opposite ends with inlet and outlet openings and-pro gressively increasing in diameter from adjacent said respective openings to'a'maximum diameter 1 ataizoneintermediate said ends, said maximum diameter being at least twice the diameter of said inlet opening and said'outlet opening being of a diameter at least substantially as large as the diameter, an outer series of axially spacedannu- I lar baffles integrally secured within said casing and directed inwardly thereof and toward said outlet opening with their inner peripheral edges spaced inwardly from and conforming to thegenveral"contour of said casing; and an inner series ofaxially spaced baiiiesrespectively extending in a direction outwardly from saidaxis and inclined towards'aid outlet opening, the outer peripheral edges of said inner baiiles being spaced inwardly from the inner edges of said outer battles to define a free annular passage conforming to the general contour of said casing and interconnecting said inlet and outlet passages.

'7. A muffier comprising a, substantially circular elongated casing provided at respectively 0pposite ends with inlet and outlet openings and progressively increasing in diameter from adjacent said respective openings to a maximum diameter at a zone intermediate said ends, an outer series of axially spaced annular bafiies integrally secured within said casing and directed inwardly thereof and toward said outlet opening with their inner peripheral edges spaced inwardly from and conforming to the general contour of said casing, and an inner series of axially spaced baffies respectively extending in a direction outwardly from said axis and inclined toward said outlet opening, the outer peripheral edges of said inner bafiies being spaced inwardly from the. in.- ner edges of said outer battles to define a free annular passage conforming to the general contour of said casing and interconnecting said inlet and outlet passages, said inner series of bafiies extending coaxially of and for the major part of the axial distance between said inlet and outlet openings,.and the baffles of said inner series which are contiguous said intermediate zone of said casing being of substantially greater diameter than said inlet opening.

8-. A mufiler comprising a casing member having an inlet opening and an outlet opening, and

a plurality of substantially concentric annular baflle nozzles spaced apart axially of said casing and having respective inner and outer annular side walls converging toward their outlet ends to provide a plurality of restricted annular orifices whose respective internal and external diameters increase in size from said casing inlet end to an intermediate zone of said casing and decrease therefrom toward said casing outlet end, said nozzles defining a free passage from said inlet opening to said outlet opening.

9. A mufiler 'comprisinga casing member having an inlet opening and an outlet opening, and a plurality of substantially concentric annular b aille nozzles spaced apart axially of said casing and having respective inner and outer annular side wall members converging toward their outlet ends to provide a plurality of restricted annular orifices whose respective internal and external diameters increase in size from said casing inlet end to an intermediate zone of said casing and decrease therefrom toward said casing outlet end, said nozzles defining a free annular passage becrease insize from said casing inlet end to an intermediate axial zone of said casing and progressively decrease therefrom toward said casing outlet end, said nozzles defining a continuouspassage between said inlet and outlet open-- 1 ings.

11. A muffler comprising a casing unit provided with axially disposed inlet and outlet openings and a core unit, said casing unit comprising a hollow substantially circular elongated body provided with a plurality of circumferentially extending axially spaced baflie members extending interiorly of said body and inclined toward said outlet opening, the inner edges of said baffies defining a double oppositely tapering frustoconical shape whose opposite smaller diameters are contiguous respective of said inlet and outlet openings, said core unit 'comprisingan axially disposed member rigidly supported by said casing unit and carrying fixed thereto a plurality oiaxially spaced bafiie members of generally frusto-conical shape and whose side walls taper I outwardly and toward said outlet opening, the inner edges of said core bafiies defining a double tween said inlet and outlet openings, said nozzle outer side wall members being secured at their outer peripheries to the interior of said casing member, and said nozzle inner side wall members f being supported as a unit in substantial alignment with said inlet and outlet openings for frusto-conical shape whose side walls are spaced inwardly from the inner edges of said casing baffles to provide a free passage from said inlet opening to said outlet opening.

12. A muffler comprising a casing unit provided with axially disposed inlet and outlet openings and a core unit, said casing unit comprising a hollow substantially circular elongated body provided with a plurality of lcircu'mferentially extending axially spaced baiiie members of generally frusto-conical ring shape and whose bases are attached to the inner surface of said body and whosesmall ends are directed toward said outlet opening, the inner edges of said bafiles defining a double oppositely tapering frusto-conical shape whose opposite smaller. diameters are contiguous respective of said inlet and outlet openings, the maximum diameter of said body being at least twice the diameter of said inlet opening, said core unit comprising an axially disposed member rigidly supported by said casing unit and carrying fixed thereto a plurality of axially spaced baffle members of generally frustoconical shape and whose side walls taper outwardly and toward said outlet opening, the maximum diameter of said core being greater than the diameter of said inlet opening, and the oppositely disposed end baiiles of said core being substantially smaller than the respective adjacent inlet and outlet openings, the inner edges of said core baiiles defining a double frusto-conical shape whose side walls are spaced inwardly from the inner edges of said casing baflies to provide a free passage from said inlet opening to said outlet opening.

CHARLES DEMUTH. 

